When running Ghost in development mode, you can use the {{log}} helper to output debug messages to the server console. In particular you can get handlebars to output the details of objects or the current context For example, to output the full ‘context’ that handlebars currently has access to: {{log this}} Or, to log each post in the loop: 
{{#foreach posts}}
   {{log post}}
{{/foreach}}
If you’re developing a theme and running an install using Ghost-CLI, you must use NODE_ENV=development ghost run to make debug output visible in the console.